Vertical-axis washing and centrifuging machine



June 6, 1961 R. E. CONDIT ETAL VERTICAL-AXIS WASHING AND CENTRIFUGINGMACHINE Filed Oct. 10, 1960 2 SheetsSheet 1 THEIR ATTORNEY June 6, 1961R. E. CONDIT ETAL 2,986,913

VERTICAL-AXIS WASHING AND CENTRIFUGING MACHINE Filed Oct. 10, 1960 I 2Sheets-Sheet 2 FIG-2.2

F l G. 3

LOW SPEED $P|N PAUSE. C LOW 575D SPIN E PAUSE A PAUsE B PAUSE D PAUSEOFF L WASH -5PlN l-knmsam ||C sPIN- I mu fi 1m 64 L F'L INVENTORS ROBERTE. conun- 8 :roHN a. RHODEs THEIR ATTORNEY United mtes atent ficePatented June 6, 1961 2 986 913 VERTICAL-AXIS WASllINb AND CENTRIFUGINGMACHINE Robert E. 'Condit and John E. Rhodes, Louisville, Ky., assignorsto General Electric Company, a corporation of New York Filed Oct. 10,1960, Ser. No. 61,592 1 Claim. (Cl. 68-12) This invention relates toautomatic clothes washing machines, and more particularly to anarrangement in vertical axis machines for preventing such machines fromattaining their full spin speed when the clothes unbalance in the basketis such that provision of full speed would cause undesirable striking ofthe clothes basket against the liquid retaining tub within which 1t 15nested.

A substantial amount of harm can be done, both by movement of themachine on the floor and by damage to the machine itself, if a highspeed spin is allowed to take place with an unbalance large enough tocause striking of a clothes basket rotating and gyrating at high speedagainst a stationary part within which it is positioned. One desirablemeans of taking care of this problem is to provide a suspension systemfor the moving parts of the machine which has a low critical speed, itbeing understood that unbalance-caused excursions of the moving systemare normally greatest at the critical speed. In this manner, when thecritical speed is caused to be quite low by suitable design of thesuspension systern, any striking that takes place occurs at a relativelylow speed at which, because of the small degree of fre quency and smallforce involved, there is no damage to the machine and it is not causedto walk on the floor. By tailoring the driving mechanism of the machineso that it has the capacity to drive the basket up to high speed undernormal conditions but cannot, clue to the damping effect, force itbeyond critical speed when the basket strikes a stationary part atcritical speed, an inherent safety check is put on the machine: italways continues through its cycle without need for safety switches ofthe type which shut oi the machine, and yet without any fear that damagewill be done to the machine.

There is however the factor that many commercially produced machines oftoday are of the type in which a perforated clothes basket is closelynested within an imperforate liquid containing tub. In such a machine,the liquid level in the tub and basket is the same, and if the spinningof the basket is commenced without first emptying out the liquid, theliquid may well cushion the basket to such an extent that it will passthrough critical speed without any striking occurring even though theunbalance is such that it would have caused striking if the cushioningliquid had not been present. If there is some means for causing thedrain pump to operate independently of the spinning of the basket, thisproblem is readily overcome by pumping out the liquid prior tocommencing spinning of the basket. However, a more realistic andeconomical form of commercially produced machines causes the drain pumpto be directly connected to the motor which drives the basket so thatspinning of the basket and operation of the drain pump always occurtogether. In such a structure it is, of course, impossible to drain thewater before the basket commences to spin.

It is an object of our invention to prevent, in a machine having aperforated basket nested within an imperforate tub and having adrivemechanism in which spin and operation of the drain pump always occurtogether, high speed striking of the basket against the tub.

A more specific object of our invention is to achieve this goal byproviding, in sequence, an intermediate spin speed during the removal ofsubstantially all the free standing water from the tub and then afterthat an ac celeration through critical speed so that the critical speedof the machine will be provided without a cushion of liquid to preventstriking if it is going to occur.

In one aspect of our invention, we provide a vertical axis clotheswashing machine which, in the usual manner, includes a rigid supportingframe on which spinning and washing apparatus is secured by anappropriate suspension means. The frame includes an imperforate whichextends into the receptacle, torque transmitting means connected to theagitator and to the receptacle and positioned beneath them, and areversible electric motor connected in driving relation to the torquetransmitting means. In one direction of rotation of the motor, theagitator is provided with a washing movement while for the otherdirection of motor rotation the torque transmitting means spins theclothes receptacle. The torque transmitting means and the motor areformed to provide the receptacle with either one of two spin speeds, alower speed for delicate garments and a higher speed for the normalarticles. The suspension means and the washing and spinning apparatusare so formed that the critical speed of the machine is substantiallylower than the higher rotational speed of the receptacle which may beprovided by the motor and torque transmitting means, and somewhat lowerthan the low spin speed. A pump is directly driven by the motor and isformed so that when the motor rotates in the direction to cause spin italso causes the pump to drain the tub.

In order to prevent harmful high speed striking of the receptacleagainst the tub in this machine, We provide means controlling theoperation of the motor which causes, in sequence, a low speed spinduring removal of free-standing water from the tub, a pause to permitthe basket speed to decrease through critical, and then an accelerationthrough critical speed to the selected speedafter the removal ofsubstantially all the freestanding water. This insures that if theunbalance is such as to cause striking at high speed, striking willoccur at the. critical speed since, as is known, the unbalance-causedexcursions of the moving system are then substantially at their greatestamplitude. In combination with this structure, we proportion the drivingcapacity of the motor so that it is incapable of accelerating thereceptacle to full speed when the damping which results from sub--stantial striking of the receptacle against the tub occurs. In thismanner, in case of excessive unbalance the full spin operation will beprovided at critical speed where the striking or rubbing can do no harmto the machine. This permits the washing operation to be completed andterminated without the necessity of such costly additional items asunbalance switches.

The subject matter which we regard as our invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention itself, however, both as to itsorganization and method of operation maybest be understood by referenceto the following description taken in conjunction with the accompanyingdrawings.

In the drawings,

FIGURE 1 is a side elevational view of 'a clothes washing machine of thetype which may suitably include our improvement, the view beingpartially broken awayand partially in section toillustrate details;-

FIGURE 2 is a schematic diagram of an electrical'control circuitincorporating our invention, which circuit 18 incorporated in themachine of FIGURE 1; and

FIGURE 3 is a schematic view of a development of the cam surfaces usedin the control of the timer operated switches of FIGURE 2, therebyindicating the operations of the switches by cams throughout the cycle.

Referring now to FIGURE 1, we have shown therein an agitator typeclothes washing machine 1 having a conventional basket or clothesreceiving receptacle 2 provided over its side and bottom walls withperforations 3 and disposed within an outer imperforate tub or casing 4.The basket 2 may be provided with a suitable clothes retaining member 5for preventing clothes from being floated over the top of the basket,and with a balance ring 6 to help steady the basket when (as will beexplained) it is rotated at high speed.

Tub 4 is rigidly mounted within an appearance cabinet 7 which includes acover 8 hingedly mounted in the top portion 9 of the cabinet forproviding access to an opening 10 to the basket 2. As shown, a gasket 11may be provided so as to form a seal between the top of tub 4 andportion 9 of the cabinet thereby to prevent escape of moisture and moistair into the cabinet around the tub The rigid mounting of tub 4 withinthe cabinet 7 may be effected by any suitable means. As a typicalexample of one such means we have provided strap members 12, each ofwhich is secured at one end to an inturned flange 13 of the cabinet andat its other end to the outside of tub 4. At the center of basket 2there is positioned a vertical axis agitator 14 which includes a centerpost 15 and a plurality of curved Water circulating vanes 16 joined attheir lower ends by an outwardly flared skirt 17.

Both the clothes basket 2 and the agitator 14 are rotatably mounted. Thebasket is mounted on a flange 18 of a rotatable hub 19, and the agitator14 is mounted on a shaft (not shown) which extends upwardly through thehub 19 and through the center post 15 and is secured to the agitator soas to drive it. During the cycle of operation of the machine 1, water isintroduced into the tub 4 and basket 2, and the agitator 14 is thenoscillated back and forth on its axis, that is, in a horizontal planewithin the basket, to wash the clothes therein. Then, after apredetermined period of this washing action, basket 2 is rotated at highspeed to extract centrifugally the washing liquid from the clothes anddischarge it to drain. Following this extraction operation, a supply ofclean liquid is introduced into the basket for rinsing the clothes andthe agitator is again oscillated. Finally, the basket is once morerotated at high speed to extract the rinse water.

The basket 2 and agitator 14' may be driven through any suitable meansfrom a reversing motor as the specific transmission means is not afeature of'the present invention. By way of example, we have shown themas driven from a reversible motor 20- through a drive including a clutch21 mounted onthe motor shaft. As will be more fully discussed herebelow,the motor is tailored so as to be used to its full extent when itaccelerates the basket Zup to spin speed, and in order to assist thisrelatively light motor during its starting, clutch 21 allows the motorto start without a load and then accept the load' as it comes up tospeed. A suitable belt 22 transmits power to a transmission assembly. 23through apulley 24. Thus, depending upon the direction of; motorrotation, pulley 24 of transmission 23 is driven in. oppositedirections.

Transmission clutch 21 is also a two speed clutch so as to provide forvarious operatingspeedsofthe machine, and inthis connection a-solenoidmember25 having a plunger 26 which operates a control member 27 throughaspring 28 is provided in order to achieve a two'speed operation.Specifically, in the ill-ustratedmachine, when solenoid25 isdeenergized-the clutch21 provides a direct drive betweenmotor-ZO andpulley'24, andwhensolenoidZd is energizedclutch 21 provides a.reducedspeed drive-- to pulley 24. A two speed clutch of this type,particularly suited for use in the illustrated machine, is described indetail and claimed in Patent 2,869,699 issued to John Bochan on January20, 1959 and assigned to General Electric Company, assignee of thepresent invention.

The transmission 23 is so arranged that it supports and drives both theagitator drive shaft and basket mounting hub 19. When motor 20 isrotated in one direction the transmission causes agitator 14 tooscillate in a substantially horizontal plane within the basket 2.Conversely, when motor 20 is driven in the opposite direction, thetransmission rotates the wash basket 2 and agitator 14 together at highspeed for centrifugal liquid extraction. While the specific type ofdrive mechanism used does not form part of the invention, reference ismade to Patent 2,844,225 issued to James R. Hubbard et al. on July 22,1958 and owned by the General Electric Company, assignee of the presentinvention. That patent discloses in detail the structuralcharacteristics of a transmission assembly suitable for use in theillustrated machine.

In addition to operating the transmission 23, as described, motor 20also provides a direct drive through a flexible coupling 29 to a pumpstructure, generally indicated at 30 and which may include two separatepumping units 31 and 32 both operated simultaneously in the samedirection by motor 20. Pump 31 has an inlet which is connected by aconduit 33 to an opening 34 formed at the lowermost point of tub 4. Pump31 also has an outlet which is connected by a conduit 35 to a suitabledrain (not shown). The pump 32 has an inlet connected by a conduit 36 tothe interior of t-ub 4 and an outlet connected by conduit 37 to a nozzle38. The pumps are formed so that in the spin direction of rotation pump31 will draw in liquid from opening 34 through conduit 33 and thendischarge it through conduit 35 to drain, and in the other direction ofrotation pump 32 will draw in liquid through conduit 36 and discharge itthrough conduit 37 and nozzle 38, each of the pumps being substantiallyinoperative in the direction of rotation in which it is not used.

Nozzle 38 is positioned to discharge into a filter pan 39 secured on thetop portion 40 of agitator 14 so as to be movable therewith. With thisstructure, then, when the motor is rotating so as to provide agitation,pump 32 draws liquid through conduit 36 from tub 4 and discharges itthrough conduit 37 so that the liquid passes from nozzle 38 into filterpan 39, and then down through a number of small openings 41 provided inthe bottom of the filter pan and back into basket 2. In this manner, thefilter pan 39, with its small openings 41 and its upstanding side wall42, causes lint which is separated from the clothes during the washingoperation to be filtered out of the water and thus prevents it frombeing redeposited on the clothes. This type of structure is more fullydescribed and claimed in Patent 2,481,979 issued to Russell H. Colley onSeptember 13, 1949 and assigned to General Electric Company, owner ofthe present invention.

Themotor 20, clutch 21, transmission 23, basket 2 and agitator 14 form asuspended washing and centrifuging system which is supported by thestationary structure of the machine (which includes tub 4) so as topermit isolation of vibrations from the stationary structure; it will beunderstood that such vibrations occur primarily as a result of highspeed spinning of basket 2 with a load of clothes therein as mentionedvabove. While any suitable suspension structure which Willprovide the.desired low critical speed (to be further discussed herebelow) may beused, we prefer to use a suspension Structure which includes a bracketmember 43with transmission 23 mounted on top thereof and motor 20mounted to the underside thereof. The bracket member in turn is securedto upwardly extending rigid members 44, and each of the two upwardlyextending-members 44 is'connected to a cable 45 supported'fromthe top ofthe'machine. While only aportion of the suspension system is-shown=inthedraw-- ing, such a vibration isolating system is fully described andclaimed in application Serial No. 843,611 for Vibration IsolatingSystem, filed on September 21, 1959 by John Bochan and assigned toGeneral Electric Company, assignee of the present invention, referencehereby being made to that application. Such a suspension system providesfor flexible support of the motor transmission, agitator and basket soas to isolate the vibrations in that system from the casing of themachine and so as to provide a low range of critical speeds.

In order to accommodate the movement which occurs between basket 2 andtub 4 without any danger of leakage between them, the stationary tub 4is joined to the upper part of transmission 23 by a suitable flexibleboot member 46. Boot 46 may be of any suitable configuration, many ofwhich are known in the art to permit relative motion of the parts towhich it is joined without leakage therebetween. A suitable and highlyeflfective structure of this type is described and claimed inapplication Serial No. 822,493 filed on June 24, 1959, now Patent No.2,959,966, for Joining Member For Providing a Flexible ConnectionBetween Two Relatively Movable Members, by John Bochan and assigned toGeneral Electric Company, assignee of the present invention.

Completing now the description of the machine as illustrated in FIGURE1, hot and cold water may be supplied to the machine through conduits 47and 48 which are adapted to be connected respectively to sources of hotand cold water (not shown). Conduits 47 and 48 extend into aconventional mixing valve structure 49 having solenoids 50 and 51 sothat energization of solenoid 50 permits passage of hot water throughthe valve to a hose 52, energization of solenoid 51 permits passage ofcold water through the valve, and energization of both solenoids permitsmixing of hot and cold water in the valve and passage of warm water intohose 52. Hose 52 communicates with a nozzle 53 positioned to dischargeinto basket 2 so that when one or both of the solenoids 50 and 51 isenergized water enters into basket 2 and tub 4.

The level to which the water rises in the basket and tub may becontrolled by any suitable means. One typical means of doing this is toprovide an opening 54 in the side of tub 4 adjacent the bottom thereof,the opening 54 being connected through a conduit 55 and a tube 56 to aconventional pressure sensitive device (shown only schematically, inFIGURE 2, by the numeral 56a) which may be positioned within thebacksplasher 57 of machine 1. In the conventional manner, as the waterrises in basket 2 and tub 4, it exerts increasing pressure on a columnof air trapped in tube 56, and at a predetermined pressure level thecolumn of air then trips the pressure sensitive mechanism to shut offwhichever solenoids 50 and 51 may be energized. The backsplasher 57 mayhave suitable manual controls, such as that shown at 58, extendingtherefrom so that the particular type of cycle, including washing andspin speeds, water temperatures, water level within the tub 4 and basket2, etc., may be controlled to efiect the washing of different types offabrics.

Referring now to FIGURE 2, the electrical control system for the machineof FIGURE 1 will be described. In connection with the circuit of FIGURE2, it will be understood that present-day washers often include variousimprovements such as control panel lights, bleach dispenser controls,etc., which do not relate in any way to the present invention, and thatto some extent these have been omitted for the sake of simplicity andease of understandmg.

In order to control the sequence of operation of the components ofmachine 1, the circuit includes a timer motor 59 which drives aplurality of cams 60, 61, 62, 63 and 64. These cams, during theirrotation by the timer motor, actuate various switches (as will bedescribed), causing the machine to pass through an appropriate cycle ofoperations, first washing the clothes, next extracting water from them,then rinsing the clothes in clean water,

and finally extracting the rinse water from the clothes. The operatingsurfaces of the ditferent cams are shown in developed form in FIGURE 3and will be further discussed herebelow in connection with thedescription of the operation of the machine.

The electric circuit as a whole is energized from a power supply (notshown) through a pair of conductors 65 and 66. Cam 60 controls a switch67 which includes contacts 68, 69 and 70. When the cam has assumed aposition where all three contacts are separated, machine 1 has beendisconnected from the power source and is inoperative. When operation ofmachine 1 is initiated, as will be explained below, switch 67 iscontrolled by cam 60 so that contacts 68 and 69 are engaged. When themain switch 71 is closed (by one of the controls 58), power is thenprovided to the control circuit of the machine from conductor 65 throughcontacts 68 and 69. From contact 69 the circuit extends throughconductor 72 and control solenoid 50 to a manually operable switch 73;also, from conductor 72, a circuit extends through control solenoid 51to a manually operable switch 74. In

addition, a circuit is completed from conductor 72 through solenoids 50and 51 to a pair of stationary contacts 75 and 76 respectively, thesetwo contacts forming a part of a switch 77 controlled by a cam having amovable contact 78 controlled by cam 61. When contact 78 is in its upposition engaging contact 76, it completes a connection through solenoid51 to conductor 79, and when contact 78 is in its down position engagingcontact 75, it completes a connection through solenoid 50 to theconductor 79. It will thus be seen that when switches 73 and 74 areopen, euergization of solenoids S0 and 51 is under the control of switch77. When switch 73 is closed, the hot water solenoid is energizedindependently of the position of switch 77, and when switch 74 is closedthe cold water solenoid is energized independently of the position ofswitch 77 From the hot and cold water solenoids the energizing circuitthus extends through conductor 79, and then through a coil 80 of a relay81, the main winding 82 of motor 20, a conventional motor protector 83,a conductor 84, a switch 85 controlled by cam 63, switch 71, and theconductor 66.

The motor 20 is of the conventional type which is provided with a startwinding 86 which assists the main winding 82 during the starting of themotor and is energized in parallel therewith. When a relatively highcurrent passes through the relay coil 80 it causes the relay contact 87to be closed; thus permits an energizing circuit for the start windingto be completed in parallel with the main winding through a contact 88of a switch generally indicated at 89 and which is controlled by cam 62,contact arm 90, the relay contact 87, the start winding 86, contact arm91, and contact 92 of switch 8 9. A circuit is also completed inparallel with motor 20 from conductor 79 through the timer motor 59.

The relay coil 80 is designed to close contact 87 when a relatively highcurrent, of the level demanded by the motor when the rotor is rotatingbelow a predetermined speed, is passing through it. At other times, whenthere is no current passing through the relay coil 80 or when thecurrent is below the required energizing level as is true in the runningspeed range of the motor, the contact 87 is open.

When the main winding 82 of motor 20 is in series with the valvesolenoids 50 and 51 as described, a much lower impedance is presented inthe circuit by the motor 20 than is presented by the valve solenoids. Asa result, the greater portion of the supply voltage is taken up acrossthe solenoids and relatively little across the motor. This causeswhichever of the solenoids which is connected in the circuit to beenergized sufliciently to open its asso-. ciated water valve. -As aresult, water at a suitable tem perature is admitted to the machinethrough outlet-53, motors 26 and 59 remaining inactive.

This action continues, with the circuitry thus arranged, so that thewater pours into the basket 2 and tub 4. Because of the perforations 3,the water rises ih both basket and tub at the same rate. As the head ofwater acting on the column of air trapped in tube 56 increases, thepressure of this air increases until it actuates the pressure sensitiveswitch 56a provided within backsplasher 57. When switch 56a closes, itthen provides a short circuit across the solenoids directly fromconductor 72 to conductor 79 so that, with the solenoids thus excludedfrom the effective circuit, they become deenergized and a high potentialdrop is provided across winding 82 of the motor 20. This causes therelay coil 80 to close contact 87 to start the motor 20, while at thesame time timing motor 59 starts so as to initiate a sequence ofoperations.

Completing the description of the circuit of FIGURE 2 prior todescribing in full its operation, it is to be observed that the switch85 is in series with the main motor 26 but is not in series with thetiming motor 59. Thus, by the opening of this switch, the operation ofmotor is stopped. The timer motor will nonetheless continue to operate,as a result of the fact that the timer motor 59 is deliberately providedwith an impedance much greater than that of the valve solenoids so thatit will take up most of the supplied voltage and will continue inoperation, leaving so little voltage across the solenoids that they donot operate their respective valves.

A further point of the circuit of FIGURE 2 is that when switch arms 99and 91 are moved by cam 62 to engage contact 92 and a contact 94respectively, the polarity of the start winding is reversed. The circuitfrom conductor 79 then proceeds through contact 94, contact arm 91, thestart winding 86, relay contact 87, contact arm 90, and contact 92 tothe protective device 83 and conductor 84. Thus, provided motor 20 isstopped or slowed down so that relay contact 87 is closed, the reversalof switch S9 is efiective to cause the motor 20 to rotate in theopposite direction than that previously provided once the motor isstarted up again.

In order to energize the motor 20 independently of the water levelswitch 56a and the valve solenoids when spin is to be provided, cam 69is formed so that it may cause all three contacts 68, 69 and 70 ofswitch 67 to be closed during the extraction or spin step. This causesthe power to be supplied directly through contact 70 to conductor 79 andthe motors, rather than through the water level switch or the valvesolenoids.

In order to attain maximum washing effectiveness for diiferent types ofloads, operation of the agitator mechanism during washing and rinsingsteps may be provided either at high speed or low speed, and the spinspeed of the basket during spinning may also be selected as either highor low. As stated above, solenoid is provided in connection with clutch21 in order to achieve the two output speeds of the clutch to providefor high and low speed agitation and high and low speed spin operations.A manually operable switch 95 controls the agitation speed, and amanually operable switch 96 controls the spin speed provided thecontacts 97 and 98 of a switch 99 controlled by a cam 64 are in theposition shown. When switch 95 is connected to contact 190 and conductor101, solenoid 25 is not energized during agitation and consequently highspeed agitation is provided; when switch member 95 engages contact 192and conductor 84, the solenoid is energized during agitation and lowspeed agitation is provided. in the same manner, connection of switch 96with contact 193 and conductor 191 prevents energization of solenoid 25during spin and a high speed spin is provided, while connection ofswitch arm 96 to contact 104 causes energization of solenoid 25 duringspin and a low spin speed is provided. The precise mannor in which thesetting of the switches 95 and 96 controls the" energizatign of solenoid25 is described in substantial detail-and is claimed in Patent 2,950,612issued on August 30, 1960 to"Wallace Hi Hensha'w, and-assigned toGeneral Electric Company, owner of the present invention.

As the means of providing the important speed con-' trolling feature ofour invention, we provide the switch 99 which has the contacts 97 and 98as previously mentioned. Contact 97 is in series with the manuallyoperable switch 96 and thus controls the effectiveness of switch 96.When contact 97 is completing a circuit to switch 96, contact 98 isopening a circuit which, by means of a conductor 105, constitutes a pathin parallel with switch 96 to conductor 79. When the switch 99 is movedby cam 64 so that contact 97 disconnects switch 96, contact 98 is thenin position to complete a circuit through conductor 105 from thesolenoid 25 to conductor 79, and as explained this is effective to causea slow spin to be provided.

Referring now to FIGURE 3 in conjunction with FIGURE 2, a sequence ofoperation of the machine 1 will be described. It will be assumed thatthe timer has been set at WASH so that cam 64} has caused contacts 68and 69 to be closed, cam 61 has caused contact 78 to engage contact '75,cam 62 has positioned switch 89 as shown, cam 63 has closed switch 85,and cam 64 has moved switch 99 to the position shown. At this point thefirst step which takes place is the filling of the machine with water bythe energization of the solenoids and the consequent inactive status ofmotors 20 and 59 as previously explained. As also previously explainedthe filling continues until the closure of switch 56a at which point thesolenoid or solenoids are deenergized and consequently motors 20 and 59are energized, the energizetion of motor 20 being in the direction tocause an agitation operation which, with manual switch 95 in theposition shown, will be at the higher of the two available speeds.

This washing action continues for a predetermined time until pause A isreached, at which time cam 63 opens switch This stops the operation ofmotor 20 and consequently there is no further agitation although, asexplained, the timer continues to operate. During pause A cam 60 movesto its spin position in which it closes all three contacts 68, 69 and70, cam 62 reverses switch 89, and cam 64 moves contacts 97 and 98 totheir open and closed positions respectively.

As a result of this, when at the end of pause A i switch 85 is reclosedby cam 63, motor 20 is energiied once again (by virtue of the bypassingof solenoids 50 and 51 by switch 67) but in the opposite direction. Asexplained, this causes spinning of basket 2 and also operation of pump31 to pump out liquid from tub 4 to the by the contact 98 and conductor105. Thus, a low speed spin is commenced regardless of what kind ofspinning operation was initially selected. Of course, the'pumping rateis unatiected since the motor continues to operate at the same speed andthe pumping rate is dependent only upon operation of the motor.

, This continues for a brief period of time; one minute, for example,has been proven to be entirely suflicient for pump 31 to removesubstantially all freestanding water from tub 4 in the machine describedso that the water does not have a cushioning effect on theunbalance-caused movement of basket 2. At the end of this brief periodof time, cam '63 opens switch 85 so that the motor 20 is deenergized andthe spinning of basket 2 ceases. During the resulting pause, basket 2slows down below the critical speed and cam 64 moves contacts 98 and 97back into the position shown in FIGURE 2 so that the position of switch96 once again controls the spin speed. I

Thereafter at the end of the pause B, the cam 63 recloses switch 85 anda spin operation is recommenced. This time; of" course, with'the waterhaving already been puniped ont; the" critical s'p'edof rot'atioi'i erbasket 2' is reached with substantially no freestanding water in the tub4. As a result, in view of the fact that unbalancecaused excursions ofbasket 2 are substantially at a maximum at the critical speed, if theunbalances are great enough to cause a striking or rubbing of basket 2against the inner wall of tub 4, it will occur at the relatively lowspeed which the appropriate design of the suspension system permits tobe provided as the critical speed for the system.

It will be recognized that a substantial amount of damping, that is,dissipation of energy, will result from striking or rubbing of thebasket 2 against the tub 4 as a result of unbalance-caused excursions.The damping efiect provided by the rubbing of basket 2 against tub 4 isso calibrated relative to the load capacity of clutch 21 that the amountof damping provided prevents the motor 20 from increasing the basketspeed past critical if any substantial amount of striking or rubbing ofthe basket and the tub is occurring. As a result, in the event ofexcessive unbalance, the full first spin operation, as shown in FIGURE3, will take place substantially at the critical speed which is so lowthat the rubbing or striking does not cause any ill effect to themachine. However, if the unbalances in the machine were small enough toallow high speed operation without striking, then the machine will gothrough the critical speed rotation of basket 2 without strikingoccurring. When this happens, the motor 20 has suflicient capacity toraise the basket speed to the full desired value, generally on the orderof several hundred r.p.m., that is, substantially more than the criticalspeed.

In either event, the spin operation will continue until pause C, atwhich time switch 85 is again opened by cam 63, cam 60 disconnectscontact 70, cam 62 reverses the start Winding connections, and cam 61moves switch 78 into engagement with contact 76. When the pause C isended by the closing of switch 85, one or both of solenoids 56 and 51are energized in the same manner as previously, the only difierencebeing that if both switches 73 and 74 are open the cold water solenoid51 will be energized instead of the hot water solenoid 50 which waspreviously energized. In this manner, the basket will be filled withcold water, and when the proper level has been reached the motors 59 and20 will start to provide a timed rinse operation.

After the rinse, a fourth pause D is provided during which thetimer-operated switches, with the exception of switch 77, are positionedin the same manner as they were during pause A." Thereafter, the samesequence of a low speed spin, then another pause E, and then anacceleration through the critical speed without a substantial amount ofwater being present in the tub 4 are provided. At the end of the secondfull spin, the machine is turned off with the clothes in a clean rinsedcondition and damp dried by the centrifugal force of the last spin.

It will be seen that our invention provides a means of avoiding damageto the machine by high speed striking, while at the same time avoidingthe substantial added expense of either a neutral in the transmission oran unbalance switch.

It will be understood that while in accordance with the patent statuteswe have described what at present is considered to be the preferredembodiment of our invention, it will be obvious to those skilled in theart that various changes and modifications may be made herein withoutdeparting from our invention, and it is therefore aimed in the appendedclaim to cover all such changes and modifications as fall within thetrue spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

A vertical axis clothes washing machine comprising: a rigid supportingframe, washing and spinning apparatus, and suspension means securingsaid apparatus on said frame in vibration isolating relation thereto;said frame including an imperforate liquid receiving tub; said washingand spinning apparatus including a perforated clothes receptacle nestedwithin said tub, movably mounted agitator means extending into saidreceptacle, driving means including a reversible electric motor, saiddriving means being connected to said receptacle and said agitator meansin said receptacle and positioned therebelow, said driving meansproviding said agitator means with a washing movement for one directionof motor rotation and spinning said receptacle for the other directionof motor rotation, said driving means being formed to provide saidreceptacle alternatively with either one of two spin speeds in saidother direction of motor rotation; said suspension means and saidapparatus being formed so that said apparatus has a critical speed lowerthan either of said rotational speeds provided by said driving means tosaid receptacle; pump means connected to said tub and directly driven bysaid motor, said motor causing said pump means to drain said tub duringrotation in said other direction; means controlling operation of saiddriving means including manually operable means for selecting one ofsaid spin speeds, said controlling means providing in sequence the lowerof said spin speeds during removal of substantially all free-standingwater from said tub independently of the selection made by said manuallyoperable means, a decrease in basket speed below critical speed, andthen acceleration through critical speed to the selected speed aftersuch removal; the capacity of said driving means being so limited as toprevent acceleration to full speed in response to striking and rubbingof said receptacle within said tub at critical speed.

References Cited in the file of this patent UNITED STATES PATENTS2,760,639 Haverstock Aug. 28, 1956 2,859,877 Sisson Nov. 11, 19582,869,699 Bochan Jan. 20, 1959 2,875,526 Engel et a1. Mar. 3, 19592,950,612 Henshaw Aug. 30, 1960

